On 18/08/13 07:37, rupert THURNER wrote:
a trace may reveal locking problems in case of multi threading
CPU usage was high, so there were no locking problems.
, string operations causing OS calls for every character,
System CPU was negligible.
creating and garbage collecting objects, and 100s of others.
Profiling of relevant requests, with the site up, could answer this and hundreds of similar questions, more effectively than a single stack trace collected from a process with high CPU. It will not answer the question "why was Google downloading these files with such high concurrency", which apparently is the relevant question here.
it is not necessary to wait until it stalls again to get the trace.
There was no stall -- it was a CPU overload, which is a different thing. Collecting stack traces certainly can help with stall diagnosis.
-- Tim Starling